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a97bdbda BA |
1 | import { ChessRules } from "@/base_rules"; |
2 | import { ArrayFun } from "@/utils/array"; | |
3 | import { randInt } from "@/utils/alea"; | |
4 | ||
32f6285e | 5 | export class GrasshopperRules extends ChessRules { |
7e8a7ea1 | 6 | |
b627d118 BA |
7 | static get HasEnpassant() { |
8 | return false; | |
9 | } | |
10 | ||
32f6285e BA |
11 | static get PawnSpecs() { |
12 | return Object.assign( | |
13 | {}, | |
14 | ChessRules.PawnSpecs, | |
1c15969e | 15 | { promotions: ChessRules.PawnSpecs.promotions.concat([V.GRASSHOPPER]) } |
32f6285e BA |
16 | ); |
17 | } | |
18 | ||
a97bdbda BA |
19 | static get GRASSHOPPER() { |
20 | return "g"; | |
21 | } | |
22 | ||
23 | static get PIECES() { | |
24 | return ChessRules.PIECES.concat([V.GRASSHOPPER]); | |
25 | } | |
26 | ||
27 | getPpath(b) { | |
28 | return (b[1] == V.GRASSHOPPER ? "Grasshopper/" : "") + b; | |
29 | } | |
30 | ||
31 | getPotentialMovesFrom([x, y]) { | |
32 | switch (this.getPiece(x, y)) { | |
33 | case V.GRASSHOPPER: | |
34 | return this.getPotentialGrasshopperMoves([x, y]); | |
35 | default: | |
36 | return super.getPotentialMovesFrom([x, y]); | |
37 | } | |
38 | } | |
39 | ||
40 | getPotentialGrasshopperMoves([x, y]) { | |
41 | let moves = []; | |
42 | // Look in every direction until an obstacle (to jump) is met | |
43 | for (const step of V.steps[V.ROOK].concat(V.steps[V.BISHOP])) { | |
44 | let i = x + step[0]; | |
45 | let j = y + step[1]; | |
46 | while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) { | |
47 | i += step[0]; | |
48 | j += step[1]; | |
49 | } | |
50 | // Move is valid if the next square is empty or occupied by enemy | |
51 | const nextSq = [i+step[0], j+step[1]]; | |
52 | if (V.OnBoard(nextSq[0], nextSq[1]) && this.canTake([x, y], nextSq)) | |
53 | moves.push(this.getBasicMove([x, y], nextSq)); | |
54 | } | |
55 | return moves; | |
56 | } | |
57 | ||
68e19a44 | 58 | isAttacked(sq, color) { |
a97bdbda | 59 | return ( |
68e19a44 BA |
60 | super.isAttacked(sq, color) || |
61 | this.isAttackedByGrasshopper(sq, color) | |
a97bdbda BA |
62 | ); |
63 | } | |
64 | ||
68e19a44 | 65 | isAttackedByGrasshopper([x, y], color) { |
a97bdbda BA |
66 | // Reversed process: is there an adjacent obstacle, |
67 | // and a grasshopper next in the same line? | |
68 | for (const step of V.steps[V.ROOK].concat(V.steps[V.BISHOP])) { | |
69 | const nextSq = [x+step[0], y+step[1]]; | |
70 | if ( | |
71 | V.OnBoard(nextSq[0], nextSq[1]) && | |
72 | this.board[nextSq[0]][nextSq[1]] != V.EMPTY | |
73 | ) { | |
74 | let i = nextSq[0] + step[0]; | |
75 | let j = nextSq[1] + step[1]; | |
76 | while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) { | |
77 | i += step[0]; | |
78 | j += step[1]; | |
79 | } | |
80 | if ( | |
81 | V.OnBoard(i, j) && | |
82 | this.getPiece(i, j) == V.GRASSHOPPER && | |
68e19a44 | 83 | this.getColor(i, j) == color |
a97bdbda BA |
84 | ) { |
85 | return true; | |
86 | } | |
87 | } | |
88 | } | |
89 | return false; | |
90 | } | |
91 | ||
92 | static get VALUES() { | |
93 | return Object.assign( | |
1eb6c9dd BA |
94 | // TODO: grasshoppers power decline with less pieces on board... |
95 | { g: 2 }, | |
a97bdbda BA |
96 | ChessRules.VALUES |
97 | ); | |
98 | } | |
99 | ||
b83a675a BA |
100 | static get SEARCH_DEPTH() { |
101 | return 2; | |
102 | } | |
103 | ||
4313762d BA |
104 | static GenRandInitFen(options) { |
105 | return ChessRules.GenRandInitFen(options) | |
3a2a7b5f | 106 | .slice(0, -2) |
1eb6c9dd BA |
107 | .replace( |
108 | "/pppppppp/8/8/8/8/PPPPPPPP/", | |
109 | "/gggggggg/pppppppp/8/8/PPPPPPPP/GGGGGGGG/" | |
110 | ); | |
a97bdbda | 111 | } |
7e8a7ea1 | 112 | |
a97bdbda | 113 | }; |